Athletes from the London 2012 Olympics team were among Waikato athletes proudly bearing the New Zealand flag, at the official opening ceremony of 2012 National Fieldays at Mystery Creek near Hamilton at noon today.

The New Zealand Air Force Cadets, described by National Fieldays Society president Lloyd Downing as an active part of the Waikato community, carried and raised the National Fieldays flag.

In officially opening the 44th National Fieldays, Primary Industries Minister David Carter said this year's Fieldays theme - the changing face of farming - highlighted exactly what was happening in New Zealand agriculture.

"The primary sector is evolving at an ever-increasing rate. Farming today is very different to, say, 20 years ago. It is more challenging than ever," Minister Carter said.

Challenges include doing more with less, more environmental considerations and the need to "come to grips" with new markets. The changing face of farming was paralleled by the change in New Zealand's traditional markets.

Trade with Asia was in essence protecting the country from financial uncertainties in Europe and the United States, with trade to China - New Zealand's second largest trading partner - up nearly 40 per cent over the past year.

This was an example of the success of the free trade agreement, Minister Carter said. Talks were underway with the Trans-Pacific Partnership countries, and with India, South Korea and Russia to negotiate free trade agreements.

Minister Carter has recently returned from a visit to Russia, where free trade agreement discussions took place. "Two-way trade now is worth $700 million. If a deal is reached, it will be Russia's first international trade deal and our exports will grow significantly.

"New Zealand is highly regarded internationally and well known as producers of some of the best food in the world."

The over-arching challenge for New Zealand now is to protect its reputation as a quality producer, Carter said. This followed the country's brand shifting to higher cost and higher quality products, aimed at the more discerning customer.

"A prosperous agriculture sector is at the heart of the growth agenda of this Government," he said.

"Our farmers and producers are the most innovative in the world. They are fully embracing the changing face of farming."

Downing said he was proud to welcome people to National Fieldays, New Zealand's premier agriculture event, which is continuing to grow with more features and demonstrations every